I've been casually browsing through the internet and Firefox Multi-Account Containers are of great help to me. I always use it to separate work, school, anime/manga and personal tabs. One thing that pains me the most is that websites that I've set default container tabs doesn't apply to its subdomains. It ain't a problem most of the time as some websites such as fandom.com(a wiki page that's more in-depth) have subdomains for different things(like, for anime, tv shows, etc.) but for some, like in my case where I access the things I selfhost are in a single domain with multiple subdomains(like domain.local for example as the homepage, admin.domain.local for administrating the site, etc.), it's really a pain. I know this is a feature and not a bug though it would be great if you can add a toggle or sth.